Display device

ABSTRACT

In a display device connected with an IC driver, particularly the reliability of connection between an IC terminal located on the outermost side and the IC driver is improved. IC terminals and flexible wiring board terminals are formed on a terminal region of a TFT substrate. A plurality of the IC terminals are formed at a predetermined pitch. The reliability of an outermost IC terminal is degraded as compared with the reliability of the other IC terminals caused by the loading effect in etching a protection insulating film. In order to prevent this degradation, a dummy terminal is formed on the outer side of the outermost IC terminal, and the loading effect on the outermost IC terminal is made equal to the loading effect on the other IC terminals. Accordingly, degradation in the reliability of the outermost IC terminal is prevented.

CLAIM OF PRIORITY

The present application claims priority from Japanese Patent ApplicationJP 2012-088871 filed on Apr. 10, 2012, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device that improves thereliability of connection in the case where an IC driver is connected byChip On Glass (COG).

2. Description of the Related Art

A liquid crystal display device includes a thin film transistor (TFT)substrate on which pixel electrodes, TFTs, and the like are formed in amatrix arrangement and a counter substrate on which a black matrix, anovercoat film, or the like is formed at locations as matched with thepixel electrodes on the TFT substrate as the counter substrate isopposite to the TFT substrate, and liquid crystals are sandwichedbetween the TFT substrate and the counter substrate. Images are formedby controlling the optical transmittance of liquid crystal molecules foreach pixel.

Since the liquid crystal display device is flat and light-weighted, theapplications of the liquid crystal display device are widely spread invarious fields from large-sized display devices such as a TV set to amobile telephone, a DSC (Digital Still Camera), and the like. In orderto externally supply electric power and signals to a liquid crystaldisplay panel, a flexible wiring board is connected to a terminal uniton the TFT substrate. Moreover, in a small-sized liquid crystal displaydevice, an IC driver is directly connected to a TFT substrate by COG.Also in the case where a flexible wiring board is connected to a TFTsubstrate as well as in the case where an IC driver is connected to aTFT substrate by COG, an anisotropic conductive film (ACF) is oftenused. The ACF includes conductive particles in a resin film, and theconductive particles conduct electricity between the terminal unitformed on the TFT substrate and the flexible wiring board, or betweenthe terminal unit and the IC driver.

A terminal is formed in which a through hole is formed on a gateinsulating film or a passivation film that is a protective film on aportion of a gate line or a drain line extending from a display regionand the through hole is covered with a conductive metal oxide. JapanesePatent Application Laid-Open Publication No. 2000-221540 describes aconfiguration in which in the case where there are conductive beadsbetween terminal through holes, a dummy through hole is formed betweenthe terminals in order to prevent connections between conductive beadsin the through holes and a flexible wiring board from being blocked bythe conductive beads between the through holes. Namely, a dummy throughhole is formed between terminals, so that such an event can be preventedby causing conductive beads to enter the dummy through hole that theelectrical continuity of conductive beads on the terminals is blocked.Therefore, it is necessary to form the dummy through hole described inJapanese Patent Application Laid-Open Publication No. 2000-221540 onboth sides of terminals.

SUMMARY OF THE INVENTION

In a small-sized liquid crystal display device, an IC driver is directlyconnected to a TFT substrate by COG. COG is a connecting method forcompression bonding of the bumps of the IC driver to terminals formed onthe TFT substrate through an ACF. FIG. 15 is a plan view and FIG. 16 isa cross sectional view in the case where a gate terminal metal that agate interconnection extends to a terminal is used for a terminal. FIG.15 is exemplary gate terminal metals using a gate line for a terminalmetal. Although there is also the case where a drain line is used for aterminal metal, an example will be described that a gate line is usedfor a terminal metal in the following description. A gate terminal metalis simply referred to as a terminal metal unless otherwise specified.

Gate lines extending from a display region are covered with a gateinsulating film and an inorganic passivation film. In a terminal unit,protective films such as the gate insulating film and the inorganicpassivation film are etched to form through holes, and terminal metalsare exposed. The exposed terminal metals are covered with a conductivemetal oxide film such as ITO (Indium Tin Oxide), and connected to thebumps of an IC driver for electrical continuity.

In FIG. 15, for the width of the through holes, a width w2 of anoutermost through hole is wider than a width w1 of a through hole on theinner side of the outermost through hole. This is called a loadingeffect, which is a phenomenon that when some through holes are disposeddensely and some are coarsely, etching advances quickly on a portionwhere through holes are disposed coarsely. In other words, since nothrough hole exists on one side of the outermost through hole,protective films are quickly etched, and the width of the through holeis increased.

FIG. 16 is a cross sectional view along a line E-E in FIG. 15. In FIG.15, the terminal metal has a structure in which a cap metal is disposedon an Al alloy. The cap metal is formed of MoCr or MoW. Even thoughmoisture or oxygen enters through pin holes or the like on ITO, the Alalloy of a layer below can be protected. It is noted that an Al alloy isformed of AlCu, AlNd, or the like. Although the electric conductivity ofan Al alloy is high, the stability against moisture or the like is low.

In FIG. 16, on portions of the terminal metals, through holes are formedon the gate insulating film and the inorganic passivation film that areprotective films. For the width of the through holes, the width w2 ofthe outermost terminal is wider than the width w1 of the terminal on theinner side. Moreover, in etching the through holes, the cap metal isalso slightly etched with an etchant. Since the etching rate is fast onthe outermost terminal, the insulating film that is a protective film isetched as well as the cap metal of the terminal metal is etched.

After forming the through holes, the terminal metals are covered withITO, for example, not shown. However, when ITO includes pin holes, forexample, moisture or oxygen enters. When the cap metal is removed withthe etchant for the insulator as removed on the outermost terminal, theAl alloy is exposed, and moisture or the like entering through the pinholes on ITO impairs the Al alloy for causing conduction failure.

In other words, in the configuration of the conventional IC driverterminal unit, the reliability of the outermost terminal is a problem.It is an object of the present invention to improve the reliability of adisplay device such as a liquid crystal display device by making thereliability of the outermost terminal equal to the reliability ofterminals on other portions.

The present invention is made to overcome the problem. Specific schemesare as follows.

(1) A display device includes a TFT substrate including a terminalregion and a display region on which a pixel including a TFT is formedin a matrix arrangement, and an IC driver is connected to the terminalregion of the TFT substrate. An IC terminal to be connected to the ICdriver is formed on the terminal region. The IC driver includes a bumpto be connected to the IC terminal. A plurality of the IC terminals areformed at a predetermined pitch, a dummy terminal is formed on an outerside of an IC terminal located on an outermost side of the plurality ofthe IC terminals, the dummy terminal is not connected to aninterconnection on the display region, and no dummy terminal is formedon an inner side of the IC terminal located on the outermost side.

(2) In the display device described in (1), the bump of the IC driver isnot connected to the dummy terminal.

(3) In the display device described in (2), the dummy terminal includesa through hole formed at least on an insulating film.

(4) In the display device described in (3), the dummy terminal includesITO covering the through hole.

(5) In the display device described in (4), in the dummy terminal, aterminal metal is formed in the through hole.

(6) In the display device described in (2), a pitch between the ICterminals is different from a pitch between the IC terminal located onthe outermost side and the dummy terminal.

(7) In the display device described in (6), a pitch between the ICterminal located on the outermost side and the dummy terminal rangesfrom 10 to 100 μm.

According to the present invention, the dummy terminal is formed on theouter side of the outermost IC terminal, and the loading effect on theoutermost IC terminal is made equal to the loading effect on the otherIC terminals, so that the reliability of the outermost IC terminal canbe maintained similarly to the reliability of the other IC terminals.Accordingly, it is possible to improve the reliability of a displaydevice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a liquid crystal display device to which thepresent invention is applied;

FIG. 2 is a perspective view of the back surface of an IC driver;

FIG. 3 is a plan view of the IC driver connected to a liquid crystaldisplay panel;

FIG. 4 is a detailed plan view of a portion A in FIG. 1;

FIG. 5 is a cross sectional view along a line A-A in FIG. 4;

FIG. 6 is a detailed diagram of a portion B in FIG. 3;

FIG. 7 is a cross sectional view along a line B-B in FIG. 6;

FIG. 8 is a detailed plan view of another example of the portion A inFIG. 1;

FIG. 9 is a cross sectional view along a line C-C in FIG. 8;

FIG. 10 is a detailed plan view of still another example of the portionA in FIG. 1;

FIG. 11 is a cross sectional view along a line D-D in FIG. 10;

FIG. 12 is a plan view of an example in which the present invention isapplied to another example of an array of IC terminals;

FIG. 13 is a plan view of an example in which the present invention isapplied to still another example of an array of IC terminals;

FIG. 14 is a cross sectional view in the case where a drain line is usedfor a terminal metal;

FIG. 15 is a plan view of a problem of IC terminals of a conventionalexample; and

FIG. 16 is a cross sectional view along a line E-E in FIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the content of the present invention will be describedin detail with reference to embodiments.

First Embodiment

FIG. 1 is an example of a liquid crystal display device to which thepresent invention is applied. FIG. 1 is a liquid crystal display devicefor use in a mobile telephone or the like, for example. In a displayregion 160 in FIG. 1, pixels including TFTs and pixel electrodes areformed in a matrix arrangement on a TFT substrate 100, and a countersubstrate 200 including color filters and the like is bonded to the TFTsubstrate 100 through a sealing material 150. A liquid crystal layer,not shown, is sandwiched between the TFT substrate 100 and the counterelectrode 200.

The TFT substrate 100 is formed larger than the counter substrate 200. Aportion where the TFT substrate 100 is provided in a single substrate isa terminal region in which IC terminals 110 to be connected to a driverIC 10 or the like and flexible wiring board terminals 130 to beconnected to an external circuit, for example, are formed. Dummyterminals 120 are formed on the outer side of the IC terminals 110.

Bumps 20 on the IC 10 are connected to the IC terminals 110. FIG. 2 is aperspective view when the IC 10 is seen from the back surface. The bumps20 are formed on the bottom face of the IC 10 as corresponding to the ICterminals 110 on the TFT substrate 100. FIG. 3 is a plan view of theliquid crystal display device in the state in which the IC 10 isconnected to the IC terminals 110 in FIG. 1. In FIG. 3, the IC 10 isconnected to the IC terminals 110 on the TFT substrate 100, and thedummy terminals 120 are formed on the outer side of the IC 10. The bumps20 on the IC 10 are not connected to the dummy terminals 120.

FIG. 4 is a plan view of a portion A in FIG. 1. In FIG. 4, the dummyterminals 120 are disposed on the outer side of the outermost ICterminal 110. On the inner side of the outermost IC terminal 110, the ICterminals 110 are continuously formed at a pitch p. Interconnectionsextend from the display region 160 to the IC terminals 110 on the upperrow, and interconnections extend to the IC terminals 110 on the lowerrow toward the direction of the flexible wiring board terminals 130. Onthe other hand, no interconnections extend from the display region 160side or the flexible wiring board terminals 130 side to terminal metals30 of the dummy terminals 120. This is because the dummy terminals 120do not serve as interconnections.

In FIG. 4, the terminal metals 30 and the interconnections are protectedby a gate insulating film and an inorganic passivation film, not shown.On the IC terminal 110, a through hole 60 is formed on the gateinsulating film and the inorganic passivation film by etching. ITO 70that is a transparent conductive film is formed so as to cover thethrough hole 60. The ITO 70 is formed to cover the end of the inorganicpassivation film as well. The ITO 70 prevents the terminal metal 30 fromcorroding with moisture or the like.

FIG. 5 is a cross sectional view along a line A-A in FIG. 4. In FIG. 5,the terminal metal 30 is formed as a stacked body of an Al alloy 31 anda cap metal 32 on the TFT substrate 100. The Al alloy 31 is formed ofAlCu or an AlNd alloy, for example, and the thickness ranges from 100 to300 nm. The cap metal 32 is formed of MoCr or MoW, for example, and thethickness ranges from 40 to 80 nm.

The through hole 60 is formed on the terminal metal 30 through the gateinsulating film 40 and the inorganic passivation film 50, and the ITO 70is formed so as to cover the through hole 60. In FIG. 5, the dummyterminal 120 is formed on the outer side of the outermost IC terminal110. The cross sectional structure of the dummy terminal 120 is the sameas the cross sectional structure of the IC terminal 110. Since the dummyterminal 120 exists on the outer side of the outermost IC terminal 110,the loading effect on the outermost IC terminal 110 in etching is thesame as the loading effect on the other IC terminals 110. Therefore, thediameter of the through hole 60 of the outermost IC terminal 110 and thestate of the cap metal 32 on the through hole 60 can be made equal tothe other IC terminals 110.

In FIGS. 4 and 5, a pitch between the IC terminals 110 is p, and a pitchbetween the outermost IC terminal 110 and the dummy terminal 120 is d.It is ideal to make the pitches d and p equal because the dummy terminal120 serves to make the loading effect on the outermost IC terminal 110the same. However, the pitches d and p do not necessarily have to be thesame. The size of the pitch d can be set in the range of 10 to 100 μm.This is because 10 μm is the size due to the accuracy in the presentmanufacture processes and it is difficult to sufficiently achieve thepurpose of making the loading effect uniform when the size exceeds 100μm.

FIG. 6 is an enlarged plan view of a region B in FIG. 3. The dummyterminals 120 exist on the outer side of the IC 10. The dummy terminal120 is configured in which the terminal metal 30 is formed in an islandshape, the through hole 60 is formed on the gate insulating film 40 andthe inorganic passivation film 50 on the terminal metal 30, and the ITO70 covers the through hole 60.

FIG. 7 is a cross sectional view along a line B-B in FIG. 6. In FIG. 7,the IC terminals 110 formed on the TFT substrate 100 are connected tothe bumps 20 on the IC 10 through an ACF 90. Conductive particles 91 inthe ACF 90 conduct electricity between the IC terminals 110 and thebumps 20 on the IC 10. As illustrated in FIG. 7, the bumps 20 on the IC10 are not connected to the dummy terminal 120. The dummy terminal 120serves to control the loading effect on the outermost IC terminal 110,and the dummy terminal 120 is unnecessary to conduct electricity.

Since the dummy terminal 120 controls the loading effect on theoutermost IC terminal 110, the dummy terminal 120 is unnecessary to havethe same shape as the shape of the IC terminal 110. Namely, it issufficient that the through hole 60 of the dummy terminal 120 is formedon the outer side of the outermost IC terminal 110 simultaneously whenthe through hole 60 is formed on the gate insulating film 40 and theinorganic passivation film 50 that are protective films. FIG. 8 is anexample that the terminal metal 30 does not exist on the dummy terminal120. Since the dummy terminal 120 is unnecessary to provide electricalconnection, it is unnecessary to provide the terminal metal 30 below thethrough hole 60.

FIG. 9 is a cross sectional view along a line C-C in FIG. 8. In FIG. 9,the terminal metal 30 does not exist below the through hole 60 of thedummy terminal 120. However, as similar to the IC terminal 110, the ITO70 exists so as to cover the through hole 60 of the dummy terminal 120.The pitch between the outermost IC terminal 110 and the dummy terminal120 is d in FIGS. 8 and 9, and the pitch d ranges from 10 to 100 μm.

FIG. 10 is the case where the dummy terminals 120 are furthersimplified, the terminal metal 30 and the ITO 70 are omitted, and onlythe through holes 60 are formed. Since the loading effect causes aproblem in the case where the through holes 60 are formed on the gateinsulating film 40 and the inorganic passivation film 50, the throughholes 60 are formed as the dummy terminals 120 when etching the gateinsulating film 40 and the inorganic passivation film 50, so that thedummy terminals 120 serve their roles.

FIG. 11 is a cross sectional view along a line D-D in FIG. 10. In FIG.11, only the through hole 60 is formed on the dummy terminal 120. InFIGS. 10 and 11, the pitch between the IC terminals 110 is p, the pitchbetween the outermost IC terminal and the dummy terminal 120 is d, andthe value of the pitch d ranges from 10 to 100 μm.

The examples in FIGS. 4, 8, and 10 are examples that the IC terminals110 are disposed in parallel with each other. The effect of the dummyterminals 120 described in the terminal arrangement in FIGS. 4, 8, 10,and the like is the same in the case where the IC terminals 110 takeother arrays. FIG. 12 is the case where the IC terminals 110 take aso-called staggered arrangement. Also in this case, the pitch betweenthe IC terminals is p, and the pitch between the outermost IC terminaland the dummy terminal is d. The configuration of the dummy terminal 120is the same as the terminal structure of the IC terminal 110 except thatno interconnection is connected to the terminal metal 30 and the dummyterminal 120 has an island shape. Also in the example in FIG. 12, thebumps 20 on the IC 10 are not connected to the dummy terminals 120.

It is noted that the terminal configuration of the dummy terminal 120 isnot limited to the case in FIG. 12, and the terminal configuration maybe the configuration as described in FIG. 8 in which the terminal metal30 does not exist, and the configuration as described in FIG. 10 inwhich none of the terminal metal 30 or the ITO 70 exists and only thethrough hole 60 exists.

Second Embodiment

The first embodiment is configured in which the dummy terminals 120 areformed on the outer side of the outermost IC terminals 110, and in thecase where the IC 10 is connected, the bumps 20 on the IC 10 are notconnected to the dummy terminals 120. On the other hand, in the casewhere a standard IC 10 is used, the IC terminals 110 formed on the TFTsubstrate 100 are not always connected to all the bumps 20 on the IC 10.Namely, there is sometimes the case where the IC terminals 110 on theTFT substrate 100 are not formed at locations corresponding to aplurality of the bumps 20 on the inner side, not the bumps 20 on the IC10 on the outermost side. In this case, the IC terminals 110 at the endof the portion where the IC terminals 110 are not formed are differentin the loading effect, and the problem as described in FIGS. 15 and 16probably occurs. FIG. 13 is an exemplary arrangement of IC terminals 110and dummy terminals 120 on a TFT substrate 100 for coping with thisproblem.

In FIG. 13, although a plurality of the IC terminals 110 are arranged ata pitch p on both sides of the TFT substrate 100, no IC terminals 110exist in an interval q. Thus, the loading effect on the IC terminal 110at the end contacting a region where no IC terminals 110 exist isdifferent from the loading effect on the other IC terminals 110. It isnoted that as in FIG. 13, the IC terminal 110 at the end contacting theregion where no IC terminals 110 exist is also referred to as theoutermost IC terminal.

In order to prevent degradation in the reliability of the outermost ICterminal 110 caused by the difference in the loading effect as describedabove, in the embodiment, the dummy terminal 120 is formed on the outerside of the outermost IC terminal 110. The configuration of the dummyterminal 120 is the same as the configuration described in FIG. 4. Thedummy terminals 120 are formed on the outer side of the left outermostIC terminal 110 and the outer side of the right outermost IC terminal110 in FIG. 13. In the embodiment, bumps 20 on an IC 10 are connected tothe dummy terminals 120. The pitch between the IC terminals 110 is p,and the pitch between the outermost IC terminal 110 and the dummyterminal 120 is d. The pitch d ranges from 10 to 100 μm. The reason isthe same as the reason described in the first embodiment.

Moreover, the dummy terminal 120 in FIG. 13 may have the terminalstructure in FIG. 8 or FIG. 10. This is because the purpose for theexistence of the dummy terminal 120 is to control the loading effect onthe outermost IC terminal 110.

The diameter of the through hole 60 of the dummy terminal 120 in thefirst embodiment and the second embodiment is not clearly described inFIGS. 4, 8, 10, 12, 13, and so on. However, generally, the diameter ofthe through hole 60 of the dummy terminal 120 is greater than thediameter of the through hole 60 of the IC terminal 110. Since the dummyterminal 120 is located at the outermost location, the diameter of thethrough hole 60 is increased depending on the difference in the loadingeffect. Furthermore, the difference in the loading effect on the dummyterminal 120 causes excessive etching, and this sometimes partiallyeliminates the cap metal 32 of the terminal metal 30. However, thecharacteristics of the display device have no problem.

In the description above, an example is described that the gate line isused for the terminal metal 30. However, the present invention is alsoapplicable to the case where the drain line is used for the terminalmetal 30. FIG. 14 is a cross sectional view of a terminal in the casewhere the drain line is used for the terminal metal 30. In FIG. 14, agate insulating film 40 is formed on the TFT substrate 100, and aterminal metal 80 is formed on the gate insulating film 40. The terminalmetal 80 in this case has the same configuration as the configuration ofthe drain line, in which a base metal 83 is formed below an Al alloy 81and a cap metal 82 is formed on the Al alloy 81. For example, the Alalloy 81 is formed of AlCu, AlNd, or the like, and the thickness rangesfrom 60 to 200 nm. For example, the base metal 83 is formed of MoCr orMoW, and the thickness ranges from 20 to 40 nm. For example, the capmetal 82 is formed of MoCr or MoW, and the thickness ranges from about40 to 80 nm.

An inorganic passivation film 50 is formed so as to cover the terminalmetal 80 as described above, and the through hole 60 is formed on theinorganic passivation film 50 at the portion of the terminal metal 80.ITO 70 is formed so as to cover the through hole 60. When the throughhole 60 is formed, the following case sometimes occurs as similar to thecase of the terminal metal 30 using the gate line, in which theoutermost IC terminal 110 is formed greater than the through holes 60 ofthe other IC terminals 110 caused by the difference in the loadingeffect, or the cap metal 82 of the terminal metal 80 is eliminated inetching the inorganic passivation film 50 for exposing the Al alloy 81.Therefore, the dummy terminal 120 is formed on the outer side of theoutermost IC terminal 110, so that the reliability of all the ICterminals 110 can be improved.

It is noted that as apparent from FIGS. 4, 8, 10, 12, 13, and so on, inthe configuration of the present application, no dummy terminals 120 areformed on the inner side of the outermost IC terminals 110.

The description hereinabove mainly describes the case where the presentinvention is applied to a liquid crystal display device. However, thepresent invention is also applicable to an organic electroluminescentdisplay device as well as a liquid crystal display device. In theorganic electroluminescent display device, pixels include TFTs for aswitching device and an organic electroluminescent layer for a lightemitting element, the pixels are formed in a matrix arrangement on adevice substrate (a TFT substrate), and a sealing substrate (a countersubstrate) is bonded to the device substrate through a sealing materialin order to protect organic electroluminescent elements from moisture orthe like. IC terminals are then formed on the device substrate (the TFTsubstrate) for connecting an IC driver. Therefore, the basicconfiguration of connecting the IC driver is the same as theconfiguration of the liquid crystal display device, and the presentinvention mentioned above is also applicable to the organicelectroluminescent display device.

1. A display device comprising: A TFT substrate formed with a displayarea where pixels are arranged in a matrix form, an IC driver connectedto the TFT substrate via an anisotropic conductive film, wherein aplurality of first electrodes connected to the IC driver are formed witha first pitch on the TFT substrate, A second electrode formed on auouter side of a first electrode located on an outermost of the pluralityof first electrodes with a second pitch, which is smaller than the firstpitch, The second electrode doesn't overlap with the IC driver.
 2. Thedisplay device according to claim 1, wherein the second electrodedoesn't overlap with anisotropic conductive film.
 3. The display deviceaccording to claim 1, wherein a first metal, a cap metal formed on thefirst metal, an insulating layer formed on the cap metal, and a metaloxide film formed on the insulating layer are formed on the TFTsubstrate, the metal oxide film and the cap metal connects via a firstthrough hole formed in the insulating layer in the plurality of thefirst electrodes, wherein, the metal oxide is formed on the TFTsubstrate via a second through hole in the second electrode.
 4. Thedisplay device according to claim 2, wherein a first metal, a cap metalformed on the first metal, an insulating layer formed on the cap metal,and a metal oxide film formed on the insulating layer are formed on theTFT substrate, the metal oxide film and the cap metal connects via afirst through hole formed in the insulating layer in the plurality ofthe first electrodes, wherein, the metal oxide is formed on the TFTsubstrate via a second through hole in the second electrode.
 5. Thedisplay device according to claim 1, where in a first metal, a cap metalformed on the first metal, an insulating layer formed on the cap metal,and a metal oxide film formed on the insulating layer are formed on theTFT substrate, the metal oxide film and the cap metal connects via afirst through hole formed in the insulating layer in the plurality ofthe first electrodes, the metal oxide film and the cap metal connectsvia a second through hole formed in the insulating layer in the secondelectrode, the cap metal at the second through hole is thinner than thecap metal at the first through hole.
 6. The display device according toclaim 2, wherein a first metal, a cap metal formed on the first metal,an insulating layer formed on the cap metal, and a metal oxide filmformed on the insulating layer are formed on the TFT substrate, themetal oxide film and the cap metal connects via a first through holeformed in the insulating layer in the plurality of the first electrodes,the metal oxide film and the cap metal connects via a second throughhole formed in the insulating layer in the second electrode, the capmetal at the second through hole is thinner than the cap metal at thefirst through hole.
 7. The display device according to claim 1, whereinthe second electrode is a dummy terminal
 8. The display device accordingto claim 2, wherein the second electrode is a dummy terminal.
 9. Thedisplay device according to claim 3, wherein the second electrode is adummy terminal.
 10. The display device according to claim 4, wherein thesecond electrode is a dummy terminal.
 11. The display device accordingto claim 5, wherein the second electrode is a dummy terminal.
 12. Thedisplay device according to claim 6, wherein the second electrode is adummy terminal